diff --git a/components/net/lwip-1.4.1/src/api/api_msg.c b/components/net/lwip-1.4.1/src/api/api_msg.c
index d4e44b9ad2..7c58a77bde 100644
--- a/components/net/lwip-1.4.1/src/api/api_msg.c
+++ b/components/net/lwip-1.4.1/src/api/api_msg.c
@@ -1235,6 +1235,7 @@ do_writemore(struct netconn *conn)
       /* partial write */
       err = ERR_OK;
       conn->current_msg->msg.w.len = conn->write_offset;
+      conn->write_offset = 0;
     }
   } else
 #endif /* LWIP_SO_SNDTIMEO */
diff --git a/components/net/lwip-head/src/api/api_msg.c b/components/net/lwip-head/src/api/api_msg.c
index f3e4f9a3a7..5442549547 100644
--- a/components/net/lwip-head/src/api/api_msg.c
+++ b/components/net/lwip-head/src/api/api_msg.c
@@ -1261,6 +1261,7 @@ lwip_netconn_do_writemore(struct netconn *conn)
       /* partial write */
       err = ERR_OK;
       conn->current_msg->msg.w.len = conn->write_offset;
+      conn->write_offset = 0;
     }
   } else
 #endif /* LWIP_SO_SNDTIMEO */